﻿#region Copyright
// Copyright 2008 Chris Varley (http://www.contractdriven.net/)
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//    http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
// Coded by: Thomas Anderson
#endregion


namespace ContractDriven.CommonAssertions
{
    #region BaseTrueFalseAssertion
    public abstract class BaseTrueFalseAssertion : IAssertion
    {
        #region Memberts
        public bool Condition  { get; protected set; }
        public string UserMessage { get; protected set; }
        #endregion
        #region Constructors       
        protected BaseTrueFalseAssertion(bool condition)
        {
            Contract.Require(Assert.IsNotNull(condition));

            Condition = condition;
        }
        #endregion

        #region IAssertion Members

        public string FailureDescription { get; protected set; }


        public abstract bool Eval();
        

        #endregion
    }
    #endregion
    #region True Assertion
    /// <summary>
    /// Describes a guarantee that an expression is true.
    /// </summary>
    public class TrueAssertion : BaseTrueFalseAssertion
    {
        #region Constructors

        /// <summary>
        /// Describes a guarantee that an expression is true.
        /// </summary>
        /// <param name="condition">The condition to be inspected</param>
        public TrueAssertion(bool condition):base(condition)
        {
            FailureDescription = Resource.TrueAssertion;
        }
#endregion
        #region Eval Method
        public override bool Eval()
        {
            return Condition;
        }
        #endregion
    }
    #endregion
    #region False Assertion
    /// <summary>
    /// Describes a guarantee that an expression is false.
    /// </summary>
    public class FalseAssertion : BaseTrueFalseAssertion
    {
        #region Constructors
        /// <summary>
        /// Describes a guarantee that an expression is false.
        /// </summary>
        /// <param name="condition">The condition to be inspected</param>
        public FalseAssertion(bool condition)
            : base(condition)
        {
            FailureDescription = Resource.FalseAssertion;
        }
        #endregion
        #region Eval Method
        public override bool Eval()
        {
            return !Condition;
        }
        #endregion
    }
    #endregion
}
